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NFSv4: include bitmap in nfsv4 get acl data

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The NFSv4 bitmap size is unbounded: a server can return an arbitrary
sized bitmap in an FATTR4_WORD0_ACL request.  Replace using the
nfs4_fattr_bitmap_maxsz as a guess to the maximum bitmask returned by a server
with the inclusion of the bitmap (xdr length plus bitmasks) and the acl data
xdr length to the (cached) acl page data.

This is a general solution to commit e5012d1f "NFSv4.1: update
nfs4_fattr_bitmap_maxsz" and fixes hitting a BUG_ON in xdr_shrink_bufhead
when getting ACLs.

Fix a bug in decode_getacl that returned -EINVAL on ACLs > page when getxattr
was called with a NULL buffer, preventing ACL > PAGE_SIZE from being retrieved.

Cc: stable@kernel.org
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Andy Adamson
2011-12-07 11:55:27 -05:00
committed by Trond Myklebust
parent 3476f114ad
commit bf118a342f
5 changed files with 89 additions and 48 deletions
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31
fs/nfs/nfs4xdr.c
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@@ -2517,11 +2517,13 @@ static void nfs4_xdr_enc_getacl(struct rpc_rqst *req, struct xdr_stream *xdr,
encode_compound_hdr(xdr, req, &hdr);
encode_sequence(xdr, &args->seq_args, &hdr);
encode_putfh(xdr, args->fh, &hdr);
replen = hdr.replen + op_decode_hdr_maxsz + nfs4_fattr_bitmap_maxsz + 1;
replen = hdr.replen + op_decode_hdr_maxsz + 1;
encode_getattr_two(xdr, FATTR4_WORD0_ACL, 0, &hdr);
xdr_inline_pages(&req->rq_rcv_buf, replen << 2,
args->acl_pages, args->acl_pgbase, args->acl_len);
xdr_set_scratch_buffer(xdr, page_address(args->acl_scratch), PAGE_SIZE);
encode_nops(&hdr);
}
@@ -4957,17 +4959,18 @@ decode_restorefh(struct xdr_stream *xdr)
}
static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
size_t *acl_len)
struct nfs_getaclres *res)
{
__be32 *savep;
__be32 *savep, *bm_p;
uint32_t attrlen,
bitmap[3] = {0};
struct kvec *iov = req->rq_rcv_buf.head;
int status;
*acl_len = 0;
res->acl_len = 0;
if ((status = decode_op_hdr(xdr, OP_GETATTR)) != 0)
goto out;
bm_p = xdr->p;
if ((status = decode_attr_bitmap(xdr, bitmap)) != 0)
goto out;
if ((status = decode_attr_length(xdr, &attrlen, &savep)) != 0)
@@ -4979,18 +4982,30 @@ static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
size_t hdrlen;
u32 recvd;
/* The bitmap (xdr len + bitmaps) and the attr xdr len words
* are stored with the acl data to handle the problem of
* variable length bitmaps.*/
xdr->p = bm_p;
res->acl_data_offset = be32_to_cpup(bm_p) + 2;
res->acl_data_offset <<= 2;
/* We ignore &savep and don't do consistency checks on
* the attr length. Let userspace figure it out.... */
hdrlen = (u8 *)xdr->p - (u8 *)iov->iov_base;
attrlen += res->acl_data_offset;
recvd = req->rq_rcv_buf.len - hdrlen;
if (attrlen > recvd) {
dprintk("NFS: server cheating in getattr"
" acl reply: attrlen %u > recvd %u\n",
if (res->acl_flags & NFS4_ACL_LEN_REQUEST) {
/* getxattr interface called with a NULL buf */
res->acl_len = attrlen;
goto out;
}
dprintk("NFS: acl reply: attrlen %u > recvd %u\n",
attrlen, recvd);
return -EINVAL;
}
xdr_read_pages(xdr, attrlen);
*acl_len = attrlen;
res->acl_len = attrlen;
} else
status = -EOPNOTSUPP;
@@ -6028,7 +6043,7 @@ nfs4_xdr_dec_getacl(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
status = decode_putfh(xdr);
if (status)
goto out;
status = decode_getacl(xdr, rqstp, &res->acl_len);
status = decode_getacl(xdr, rqstp, res);
out:
return status;